TWI537616B - Infrared cut-off filter and photography device - Google Patents

Description

Infrared cut filter and photographing device

The present invention relates to an infrared cut-off (IR-cut) filter that transmits light in the visible range and filters out infrared light.

In an optical system of a representative electronic camera such as a general camera or a digital camera, an imaging optical system, an infrared cut filter, an optical low-pass filter, and a CCD are sequentially disposed from the object side along the optical axis. (Charge-coupled device) or photographic device such as CMOS (Complementary Metal Oxygen Semiconductor) (see, for example, Patent Document 1).

The photographing device referred to herein has a sensitivity characteristic of light in a wavelength band wider than light of a wavelength band (visible region) which is visually identifiable by the human eye, and the light in the infrared region is in addition to the visible region. Will respond.

Specifically, the human eye can induce light having a wavelength in the range of about 400 nm to 620 nm in the dark, and can induce light having a wavelength in the range of about 420 nm to 700 nm in a bright place. In this regard, for example, the CCD is inductive to light having a wavelength in the range of 400 nm to 700 nm, and further to light having a wavelength exceeding 700 nm.

Therefore, the imaging device described in Patent Document 1 below is provided with an infrared cut filter in addition to the CCD of the imaging device, so that the light in the infrared region does not reach the imaging device to obtain a captured image close to the human eye.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2000-209510

However, as the infrared cut filter herein, there are an infrared absorbing glass that transmits light (visible light) in the visible region and absorbs light (infrared rays) in the infrared region, or an infrared ray blocking coating that reflects infrared rays through visible light.

As the infrared absorbing glass, for example, a blue glass in which a dye such as copper ions is dispersed is disclosed.

As the infrared cut coating, for example, a high refractive index substance such as TiO ₂ , ZrO ₂ , Ta ₂ O ₅ or Nb ₂ O ₅ is deposited, and a low refractive index substance such as SiO ₂ or MgF ₂ is alternately laminated on a transparent substrate. Dozens of dielectric multilayer films.

These infrared absorbing glass and infrared cut plating are described below with reference to FIGS. 7 and 8.

Fig. 7 shows light transmission characteristics L11 and L12 of two infrared absorbing glasses having different thicknesses. Specifically, the thickness of the infrared absorbing glass showing the light transmitting property of L11 is less than or equal to half the thickness of the infrared absorbing glass which exhibits the light transmitting property of L12.

When the infrared ray absorbing glass is used as the infrared ray blocking filter, as shown by L11 and L12 in Fig. 7, the visible light region is crossed to the infrared ray region, and the sensitivity characteristic of the human eye can be obtained to "slowly reduce the transmittance." . Further, from the comparison of L11 and L12, the transmittance in the visible light region of the infrared absorbing glass, particularly the transmittance in the wavelength band of 600 nm to 700 nm, can be recognized as the thickness is thinner.

For example, the infrared absorbing glass having the light transmitting property shown by L11 in Fig. 7 has a transmittance of about 10% for light having a wavelength of 700 nm and a light having a wavelength of about 750 nm. Therefore, the light in the infrared region cannot be sufficiently cut off, and an image of an infrared region that the human eye cannot perceive is captured by the photographing device.

On the other hand, in the infrared absorbing glass having a thickness twice or more of the infrared absorbing glass having the light transmitting property indicated by L11, as shown by the light transmitting property of L12, the transmittance of light having a wavelength of 700 nm is about 0%. Light that exceeds the wavelength of 700 nm can be sufficiently cut off.

Therefore, in the former infrared cut filter, an infrared absorbing glass having a light transmitting property indicated by L12 is used.

However, when an infrared ray absorbing glass having a light transmitting property indicated by L12 is used as the infrared cut filter, the transmittance at a wavelength of 600 nm exhibits a light transmittance of about 50%, so that it has a wavelength of about 50 at a wavelength of 640 nm. In the case of the infrared absorbing glass having a light transmitting property indicated by L11 in %, the transmittance of red visible light having a wavelength of 600 nm to 700 nm is low, and a problem that the red visible light is not sufficiently transmitted may occur. For photographic elements such as CCD or CMOS, the red sensitivity is lower than blue or green. Therefore, if the transmission of the red visible light is insufficient, the red color cannot be sufficiently perceived by the imaging element, and the image captured by the imaging device becomes a dark image in which the red color is weakened.

As described above, when the infrared ray absorbing glass is used as the infrared cut filter, it is not possible to sufficiently transmit red visible light, and the transmittance is set to 0% at a point where the transmittance is 0%.

Next, when an infrared cut-off plating layer is used as the infrared cut filter, as shown by L13 in Fig. 8, a characteristic in which the transmittance is rapidly reduced can be obtained from the visible region to the infrared region. Therefore, it is easy to sufficiently transmit red visible light and to have a transmittance of about 0% in combination with 700 nm.

However, the infrared cut-off plating does not absorb infrared rays and is cut off (interrupted), and is reflected by infrared rays. Therefore, the infrared cut-off plating promotes ghosting due to the repetitive reflection of light between the infrared cut-off plating and the imaging optical system.

The present invention has been made in view of such circumstances, and an object of the invention is to provide an infrared cut filter capable of sufficiently transmitting red visible light having a wavelength of 600 nm to 700 nm and blocking light having a wavelength exceeding 700 nm and suppressing generation of ghosts. .

The infrared cut filter according to the present invention is an infrared cut filter that cuts off infrared rays, and is characterized by comprising: an infrared absorber that absorbs infrared rays; and an infrared reflector that reflects infrared rays; and the infrared absorber has a wavelength of 620 nm to 670 nm. The transmittance of the wavelength in the band is 50% of the light transmission property; the infrared reflector has a transmittance of 50% in the wavelength band of 670 nm to 690 nm; the infrared reflector exhibits 50% The wavelength of the transmittance is longer than the wavelength at which the infrared absorbing body exhibits a transmittance of 50%; and the transmittance of the wavelength band in the wavelength range of 620 nm to 670 nm by the combination of the infrared absorbing body and the infrared ray reflector The transmittance of 50%, the wavelength of 700 nm is less than 5% of the light transmission property.

According to the infrared cut filter, the transmittance of the infrared absorber having a light transmittance of 50% in the wavelength range of 620 nm to 670 nm and the wavelength in the wavelength range of 670 nm to 690 nm The combination of 50% light-transmitting infrared reflectors can reduce the transmittance from the visible light region to the infrared region, and the transmittance at a wavelength of 700 nm becomes about 0%, which is close to the sensitivity characteristic of the human eye. Light transmission characteristics.

Further, in the infrared cut filter of the present invention, an infrared absorber having a light transmission characteristic of a transmittance of 50% in a wavelength band of 620 nm to 670 nm is used for the infrared absorber, and for example, it has the L11 of FIG. The infrared ray absorbing glass having a light transmitting property has a transmittance of about 0% (less than 5%), and can be blended at 700 nm by combining the infrared absorbing effect of the infrared absorbing body with the infrared ray reflecting action of the infrared ray reflector. Therefore, the infrared cut filter of the present invention has a wavelength in the visible light region, particularly in the range of 600 nm to 700 nm, compared with the former infrared cut filter composed of the infrared absorbing glass having the light transmitting property shown in L12 of Fig. 7 . Banding can maintain high transmittance. In short, infrared rays having a wavelength exceeding 700 nm can be cut off, and a sufficient amount of red light (light having a wavelength of 600 nm to 700 nm) which can be perceived by the imaging element of the photographing device can be transmitted. Therefore, by applying the infrared cut filter of the present invention to the infrared cut filter of the photographing apparatus, it is possible to eliminate the disadvantage that the red sensitivity of the photographing element is weak and the picture taken by the photographing apparatus is likely to become a dark image.

Further, in the infrared cut filter of the present invention, the amount of light reflected by the infrared reflector is suppressed by combining the infrared absorber with the infrared reflector. Specifically, the half-value wavelength of the infrared ray reflector 3 (the wavelength at which the transmittance is 50%) is longer than the half-value wavelength of the infrared absorbing body 2, and the infrared ray absorption in the infrared ray absorbing body 2 suppresses reflection by infrared rays. The amount of light (infrared light) reflected by the body 3. Therefore, generation of ghosts due to reflection of light by the infrared reflector can be suppressed.

Further, the transmittance at a wavelength of 640 nm is 50%, and the thickness of the infrared absorbing glass having the light transmitting property shown by L11 of FIG. 7 is used as the light transmission shown by L12 of FIG. 7 used as the former infrared cut filter. An infrared absorber having a light transmission characteristic in which the transmittance in the wavelength band of 620 nm to 670 nm is 50% in the wavelength range of 620 nm to 670 nm which is the infrared cut filter of the present invention, which is one of the thicknesses of the characteristic infrared absorbing glass. It is possible to use a thinner infrared cut filter which is thicker than the former infrared absorbing glass having the light transmitting property shown by L12 in Fig. 7 . Therefore, it is possible to provide a thickness which is the same as or thinner than the former infrared cut filter which is constituted only by the infrared absorber, and sufficiently transmits the red visible light to cut off the infrared rays, and in the visible light region, is close to the human eye. An infrared cut filter for light transmission characteristics.

Further, the infrared cut filter according to the present invention may be an infrared absorber having a light transmittance of 10% to 40% at a wavelength of 700 nm, and a transmittance of 700 nm at the infrared reflector. Less than 15% light transmission characteristics.

The infrared cut filter is an infrared absorber that combines a light transmittance of 10% to 40% with a transmittance at a wavelength of 700 nm, and an infrared reflection with a transmittance of less than 15% at a wavelength of 700 nm. The body can be surely obtained a high transmittance in the wavelength band of the red visible light (600 nm to 700 nm).

Further, in the infrared cut filter according to the present invention, the infrared reflector may have a transmittance of 80% or more at each wavelength in a wavelength range of 450 nm to 650 nm, and may be transmitted in a wavelength band of 450 nm to 650 nm. The average rate of light transmission is above 90%.

The infrared cut filter can obtain a light transmitting property depending on the light transmitting property of the infrared absorbing body in a wavelength range of 450 nm to 650 nm, so that the transmittance is gradually reduced across the visible light region to the infrared ray region, and the wavelength can be obtained at a wavelength of 700 nm. The transmittance is about 0%, which is close to the light transmission characteristic of the sensitivity characteristic of the human eye, and a high transmittance can be obtained in the visible light region, particularly in the wavelength band of the red visible light (600 nm to 700 nm).

Further, in the infrared cut filter relating to the present invention, an infrared reflector may be provided on one main surface of an infrared absorber.

In this infrared cut filter, an infrared reflector is provided on one main surface of an infrared absorber, so that the infrared absorber and the infrared reflector can be thinned compared to the infrared cut filter provided separately. The imaging device that houses the infrared cut filter is thinned.

According to the present invention, it is possible to provide an infrared cut filter which can sufficiently transmit red visible light having a wavelength of 600 nm to 700 nm and cut off light having a wavelength exceeding 700 nm and suppress ghost generation.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<implementation type 1>

As shown in FIG. 1, the infrared cut filter 1 according to the first embodiment is disposed between the imaging optical system 4 disposed along the optical axis of the imaging optical path and the imaging device 5 in the imaging device.

The infrared cut filter 1 is composed of an infrared absorber 3 that adheres to visible rays and absorbs infrared rays, and an infrared reflector 3 that transmits visible light and reflects infrared rays. In short, the infrared cut filter 1 has a configuration in which an infrared reflector 3 is provided on one main surface of one infrared ray absorbing body 2 (the other main surface 212 of the infrared absorbing glass 21 to be described later).

The infrared absorbing body 2 is configured by forming an anti-reflection film 22 (AR plating film) on one main surface 211 of the infrared absorbing glass 21.

As the infrared absorbing glass 21, a blue glass in which a dye such as copper ions is dispersed, for example, a square thin plate glass having a thickness of 0.2 mm to 1.2 mm is used.

Further, the anti-reflection film 22 is a single layer or Al ₂ O ₂ which is formed by vacuum-depositing MgF ₂ by a conventional vacuum vapor deposition apparatus (not shown) on one main surface 211 of the infrared absorbing glass 21. It is formed by any one of a multilayer film composed of ZrO ₂ and MgF ₂ and a multilayer film composed of TiO ₂ and SiO ₂ . In addition, the anti-reflection film 22 performs a vapor deposition operation while monitoring the film thickness, and when a specific film thickness is reached, the shutter (not shown) provided in the vicinity of the vapor deposition source (not shown) is closed to stop the vapor deposition material. The evaporation is carried out. Such an anti-reflection film 22 is formed such that the refractive index N in the atmosphere is larger than the refractive index of the atmosphere (about 1.0) and smaller than the refractive index of the infrared absorbing glass 21.

The infrared absorber 2 has a light transmittance of 50% in a wavelength band of 620 nm to 670 nm and a light transmittance of 10% to 40% at a wavelength of 700 nm. Moreover, in the light transmission characteristics of the infrared absorber 2, the wavelength in the wavelength range of 400 nm to 550 nm is 90% or more.

The infrared reflecting body 3 is formed with an infrared reflecting film 32 on one main surface 311 of the transparent base 31.

As the transparent substrate 31, a colorless transparent glass that transmits visible light and infrared rays, for example, a square thin plate glass having a thickness of 0.2 mm to 1.0 mm is used.

As shown in FIG. 2, the infrared reflecting film 32 is a multilayer film in which a first film 321 made of a high refractive index material and a second film 322 made of a low refractive index material are laminated to form a multilayer film. Further, in this embodiment 1, the first film 321 uses TiO ₂ , the second film 322 uses SiO ₂ , the odd layer is TiO ₂ , the even layer is SiO ₂ , and the final layer is SiO ₂ , but in film design, finally When the layer is SiO ₂ , the odd layer is SiO ₂ and the even layer is TiO ₂ .

As a method of manufacturing the infrared ray reflection film 32, TiO ₂ and SiO _{2 are} alternately vapor-deposited on one main surface 311 of the transparent substrate 31 by a known vacuum vapor deposition apparatus (not shown), and formed as shown in FIG. 2 . A method of infrared reflecting film 32. In addition, the film thickness of each of the films 321 and 322 is adjusted, and the vapor deposition operation is performed while monitoring the film thickness, and when a specific film thickness is reached, the shutter provided in the vicinity of the vapor deposition source (not shown) is closed (not shown) The vapor deposition of the vapor deposition material (TiO ₂ , SiO ₂ ) was stopped.

In addition, as shown in FIG. 2, the infrared reflecting film 32 is a plurality of layers defined by an ordinal number sequentially from one side of the main surface 311 of the transparent substrate 31, and is one layer, two layers, and three layers in the present embodiment. ..... constituted. The layers of the first layer, the second layer, and the third layer are formed by laminating the first film 321 and the second film 322. By differentiating the optical film thicknesses of the laminated first film 321 and the second film 322, the thicknesses of the first layer, the second layer, and the third layer are different. Here, the optical film thickness referred to herein is obtained by the following formula 1.

[Formula 1] Nd=d×N×4/λ (Nd: optical film thickness, d: physical film thickness, N: refractive index, λ: center wavelength)

In the present embodiment, the infrared reflector 3 has a transmittance of 80% or more for each wavelength in the wavelength range of 450 nm to 650 nm, and an average transmittance of 90% or more in the wavelength range of 450 nm to 650 nm. The transmittance at a wavelength in the wavelength band of 670 nm to 690 nm is 50%, and the transmittance at a wavelength of 700 nm is a light transmission characteristic of less than 15%. Further, the infrared ray reflector 3 exhibits a wavelength of 50% transmittance, which is longer than a wavelength at which the infrared absorbing body 2 exhibits a transmittance of 50%.

The infrared cut filter 1 composed of the infrared absorber 2 and the infrared reflector 3 has a thickness of, for example, 0.4 mm to 1.6 mm. In short, the thickness of the infrared absorber glass 21 constituting the infrared absorber 2 and the thickness of the transparent substrate 31 constituting the infrared reflector 3 are the total thickness of the infrared absorber 2 and the infrared reflector 3, and are, for example, 0.4 mm to 1.6. Mm.

Next, the infrared cut filter 1 has a transmittance of 90% or more at a wavelength in a wavelength range of 450 nm to 550 nm by a combination of the light transmitting characteristics of the infrared absorber 2 and the infrared reflector 3 described above, at 620 nm. The transmittance at a wavelength in the wavelength band of -670 nm is 50%, and the transmittance at a wavelength of 700 nm is less than 5%.

Specific examples of the infrared cut filter 1 according to the first embodiment are shown as the first to third embodiments, and the wavelength characteristics and configuration of the infrared cut filter 1 according to the first to third embodiments are shown in FIG. 5 and Tables 1 to 2 below.

<Example 1>

In the first embodiment, as the infrared absorbing glass 21, a glass plate having a blue glass in which a dye such as copper ions is dispersed, a thickness of 0.8 mm, and a refractive index N in the atmosphere of about 1.5 is used. Next, on one main surface 211 of the infrared absorbing glass 21, an Al ₂ O ₃ film having a refractive index N of 1.6 in the atmosphere, a ZrO ₂ film having a refractive index N of 2.0 in the atmosphere, and a refractive index N in the atmosphere are In the order of the MgF ₂ film of 1.4, the respective films constituting the anti-reflection film 22 were formed by vacuum evaporation to obtain the infrared absorber 2.

This infrared absorbing body 2 has a light transmitting property as shown by L1 in Fig. 3 . Further, in this embodiment 1, the incident angle of the light is 0 degrees, even if the light is incident perpendicularly.

In short, the infrared absorbing glass 21 has a transmittance of 90% or more in a wavelength band of 400 nm to 550 nm, a transmittance in a wavelength band of 550 nm to 700 nm, and a transmittance of about 50% at a wavelength of about 640 nm at 700 nm. The wavelength transmittance is a light transmission characteristic of about 17%.

As the transparent substrate 31 of the infrared reflector 3, a glass plate having a refractive index N of 1.5 in the atmosphere and a thickness of 0.3 mm was used. Further, as the first film 321 constituting the infrared ray reflection film 32, TiO ₂ having a refractive index N of 2.30 in the atmosphere is used, and as the second film 322, SiO ₂ having a refractive index N of 1.46 in the atmosphere is used, and the center wavelength thereof is used. It is 688nm.

The optical film thickness of each of the films 321 and 322 is a method for producing the infrared reflecting film 32 composed of the above-described 40 layers which is a value shown in Table 1, and is applied to one main surface 311 of the transparent substrate 31. Each of the films 321 and 322 is formed to obtain an infrared reflector 3.

Table 1 shows the composition of the infrared reflecting film 32 of the infrared cut filter 1 and the optical film thickness of each of the films (the first film 321 and the second film 322).

This infrared reflector 3 has a light transmitting property as shown by L2 in Fig. 3 . In short, the light transmitting property of the infrared reflector 3 (infrared reflecting film 32) has a transmittance of about 100% in a wavelength band of 395 nm to 670 nm (a wavelength band including a wavelength band of 450 nm to 650 nm), and the wavelength exceeds At about 670 nm, the transmittance is drastically reduced, the transmittance at a wavelength of about 680 nm is 50%, and the transmittance at a wavelength of 700 nm is about 4%.

Next, as shown in FIG. 1, the other main surface 212 of the infrared absorbing glass 21 is bonded to the other main surface 312 of the transparent substrate 31 to obtain an infrared cut filter 1 according to the first embodiment having a thickness of 1.1 mm. .

The infrared cut filter 1 according to the first embodiment has light transmission characteristics as shown by L3 in Fig. 3 in which the light transmission characteristics of the infrared absorber 2 and the infrared reflector 3 are combined. In short, the infrared cut filter 1 of the first embodiment has a transmittance in a wavelength band of 400 nm to 550 nm of 90% or more, a transmittance in a wavelength band of 550 nm to 700 nm, and a transmittance at a wavelength of about 640 nm. 50%, the transmittance at a wavelength of 700 nm becomes a light transmission characteristic of about 0%.

<Example 2>

In the second embodiment, as the infrared absorbing glass 21, a glass plate having a blue glass in which a dye such as copper ions is dispersed, a thickness of 0.55 mm, and a refractive index N in the atmosphere of about 1.5 is used. Next, on one main surface 211 of the infrared absorbing glass 21, an Al ₂ O ₃ film having a refractive index N of 1.6 in the atmosphere, a ZrO ₂ film having a refractive index N of 2.0 in the atmosphere, and a refractive index N in the atmosphere are In the order of the MgF ₂ film of 1.4, the respective films constituting the anti-reflection film 22 were formed by vacuum evaporation to obtain the infrared absorber 2.

This infrared absorbing body 2 has a light transmitting property as shown by L5 in Fig. 4 . Further, in this embodiment 2, the incident angle of the light is 0 degrees, even if the light is incident perpendicularly.

In short, the infrared absorbing glass 21 has a transmittance in a wavelength band of 400 nm to 550 nm of 90% or more, a transmittance in a wavelength band of 550 nm to 700 nm, and a transmittance at a wavelength of about 650 nm of 50% at 700 nm. The wavelength transmittance is about 25% of light transmission characteristics.

As the transparent substrate 31 of the infrared reflector 3, a glass plate having a refractive index N of 1.5 in the atmosphere and a thickness of 0.3 mm was used. Further, as the first film 321 constituting the infrared ray reflection film 32, TiO ₂ having a refractive index N of 2.30 in the atmosphere is used, and as the second film 322, SiO ₂ having a refractive index N of 1.46 in the atmosphere is used, and the center wavelength thereof is used. It is 748 nm.

The optical film thickness of each of the films 321 and 322 is a method for producing the infrared reflecting film 32 composed of the above-described 40 layers which is a value shown in Table 2, and is applied to one main surface 311 of the transparent substrate 31. Each of the films 321 and 322 is formed to obtain an infrared reflector 3.

Table 2 shows the composition of the infrared ray reflection film 32 of the infrared cut filter 1 and the optical film thickness of each of the films (the first film 321 and the second film 322).

This infrared reflector 3 has a light transmitting property as shown by L6 in Fig. 4 . In short, the light transmittance of the infrared reflector 3 (infrared reflecting film 32) has an average transmittance of 10% or less in a wavelength band of 380 nm to 420 nm, and a sharp increase in transmittance when the wavelength exceeds about 430 nm, and is in the range of 450 nm to 670 nm. The wavelength band (including the wavelength band of the wavelength band of 450 nm to 650 nm) exhibits a transmittance of about 100% (average 90% or more), and the transmittance decreases sharply when the wavelength exceeds 670 nm, and the transmittance becomes 50% at a wavelength of about 680 nm. The transmittance at a wavelength of 700 nm is about 3%.

Next, as shown in FIG. 1, the other main surface 212 of the infrared absorbing glass 21 is bonded to the other main surface 312 of the transparent substrate 31 to obtain an infrared cut filter 1 according to the second embodiment having a thickness of 0.85 mm. .

The infrared cut filter 1 according to the second embodiment has the light transmission characteristics shown by L7 of Fig. 4 in which the light transmitting characteristics of the infrared absorber 2 and the infrared reflector 3 are combined. In short, the infrared cut filter 1 of the second embodiment is configured to cut light of a wavelength band of 380 nm to 420 nm in addition to light having a wavelength exceeding 700 nm, and has an average transmittance in a wavelength band of 380 nm to 420 nm. 10% or less, when the wavelength exceeds about 430 nm, the transmittance increases sharply, the transmittance in the wavelength band of 450 nm to 550 nm is 90% or more, the transmittance in the wavelength band of 550 nm to 700 nm decreases, and the transmittance at a wavelength of about 650 nm becomes 50%. The transmittance at a wavelength of 700 nm is about 0%.

<Example 3>

In the third embodiment, as the infrared absorbing glass 21, a glass plate having a blue glass in which a dye such as copper ions is dispersed, a thickness of 0.45 mm, and a refractive index N in the atmosphere of about 1.5 is used. Next, on one main surface 211 of the infrared absorbing glass 21, an Al ₂ O ₃ film having a refractive index N of 1.6 in the atmosphere, a ZrO ₂ film having a refractive index N of 2.0 in the atmosphere, and a refractive index N in the atmosphere are In the order of the MgF ₂ film of 1.4, the respective films constituting the anti-reflection film 22 were formed by vacuum evaporation to obtain the infrared absorber 2.

This infrared absorber 2 has a light transmitting property as shown by L8 in Fig. 5 . Further, in this embodiment 3, the incident angle of the light is 0 degrees, even if the light is incident perpendicularly.

In short, the infrared absorbing glass 21 has a transmittance in a wavelength band of 400 nm to 550 nm of 90% or more, a transmittance in a wavelength band of 550 nm to 700 nm, and a transmittance at a wavelength of about 670 nm of 50% at 700 nm. The wavelength transmittance is about 34% of the light transmission property.

As the transparent substrate 31 of the infrared reflector 3, a glass plate having a refractive index N of 1.5 and a thickness of 0.3 mm in the atmosphere was used in the same manner as in the first embodiment. In the same manner as in the first embodiment, as the first film 321 constituting the infrared ray reflection film 32, TiO ₂ having a refractive index N of 2.30 in the atmosphere is used, and as the second film 322, SiO having a refractive index N of 1.46 in the atmosphere is used. ₂ , the center wavelength of these is 688nm.

In the same manner as in the first embodiment, the optical film thickness of each of the films 321 and 322 is the same as that of the first embodiment, and the method for producing the infrared reflecting film 32 composed of the above-described 40 layers which is the value shown in Table 1 above is applied to the transparent substrate. One of the main faces 311 of 31 forms each of the films 321, 322, and an infrared reflector 3 is obtained.

This infrared reflector 3 has a light transmitting property as shown by L9 in Fig. 5 . As described above, in the third embodiment, the infrared ray reflector 3 is obtained in the same manner as in the first embodiment. However, the infrared ray reflector 3 (infrared reflection film 32) of the third embodiment has the infrared ray of the first embodiment due to manufacturing errors. The light transmitting property L2 (see FIG. 3) of the reflector 3 (infrared reflecting film 32) has slightly different light transmitting characteristics L9. Specifically, the light transmission characteristic L9 of the infrared ray reflector 3 (infrared reflection film 32) of the third embodiment exhibits a transmittance of 90% or more in a wavelength band of 400 nm to 440 nm, and is in a wavelength band of 450 nm to 650 nm. (specifically, in the wavelength band of 490 nm to 540 nm), the generation of ripples occurs, and the band generated by such a corrugation exhibits a transmittance of 80% or more, and an average of 90% in the wavelength range of 450 nm to 650 nm. The above transmittance. Further, the light-transmitting property of the infrared reflector 3 (infrared reflecting film 32) is drastically reduced when the wavelength exceeds about 670 nm, exhibits a transmittance of 50% at a wavelength of about 680 nm, and exhibits a transmittance of about 5% at a wavelength of 700 nm.

Next, as shown in FIG. 1, the other main surface 212 of the infrared absorbing glass 21 is bonded to the other main surface 312 of the transparent substrate 31 to obtain an infrared cut filter 1 according to the third embodiment having a thickness of 0.75 mm. .

The infrared cut filter 1 according to the third embodiment has the light transmission characteristics shown by L10 of Fig. 5 in which the light transmitting characteristics of the infrared absorber 2 and the infrared reflector 3 are combined. In short, the infrared cut filter 1 of the third embodiment has an average transmittance of 90% or more in the wavelength band of 400 nm to 550 nm, a decrease in transmittance in the wavelength band of 550 nm to 700 nm, and a transmittance at a wavelength of about 670 nm. It is 50%, and the transmittance at a wavelength of 700 nm is about 0%.

As shown in the light-transmitting characteristics L3, L7, and L10 (see FIGS. 3 to 5) of the infrared cut filter 1 of the above-described first to third embodiments, the infrared cut filter 1 according to the first embodiment can be used. The combination of the infrared absorber 2 and the infrared reflector 3 has a transmittance of 90% or more at a wavelength in a wavelength range of 450 nm to 550 nm, and a transmittance at a wavelength in a wavelength range of 620 nm to 670 nm. 50%, the transmittance at a wavelength of 700 nm is about 0% (less than 5%). In short, it is possible to obtain a light transmission characteristic which is close to the infrared ray region from the visible light region and which gently reduces the transmittance, and whose transmittance is about 0% at a wavelength of 700 nm which is close to the sensitivity characteristic of the human eye. In particular, in the infrared cut filter 1 according to the second embodiment, as described above, the transmittance in the wavelength band of 380 nm to 420 nm, specifically, the wavelength band affected by ultraviolet rays which are invisible to the human eye. Since the transmittance of the domain is suppressed to an average of 10% or less, the light transmission characteristics closer to the sensitivity characteristics of the human eye can be obtained as compared with the infrared cut filters according to the first and third embodiments.

The light transmission characteristics L3, L7, and L10 of the infrared cut filter 1 according to the first to third embodiments shown in Figs. 3 to 5 are more specifically described by comparison with the light transmission characteristic L4 of the conventional infrared cut filter.

The former infrared cut filter having the light transmission characteristics shown by L4 in FIGS. 3 to 5 is composed of an infrared absorber having an antireflection film formed on both surfaces of the infrared absorbing glass. In the conventional infrared cut filter, the infrared absorbing glass of the infrared absorbing body has a thickness of 1.6 mm, and the transmittance is about 0% at 700 nm.

On the other hand, the infrared cut filter 1 of the first to third embodiments has a thickness of half or less of the former infrared cut filter (infrared absorber) having the light transmission property of L4, and is in the visible light region, particularly 600 nm to 700 nm. In the wavelength band, the infrared absorber 2 exhibiting a higher transmittance than the former infrared cut filter, that is, the infrared absorber 2 having the light transmitting characteristics indicated by L1, L5 or L8, combined with the infrared reflector 3, and the point at which the transmittance is about 0% is matched to 700 nm.

Therefore, the light-transmitting characteristics L3, L7, and L10 of the infrared cut filter 1 according to the first to third embodiments are transmitted in the visible light region, particularly in the wavelength band of 600 nm to 700 nm, and the light transmittance of the former infrared cut filter. The characteristic L4 exhibits a high transmittance. Further, with respect to the light transmission characteristics L3, L7, and L10 of the infrared cut filter 1 of the first to third embodiments, the transmittance of light having a wavelength of 700 nm is compared with the light transmission characteristic L4 of the former infrared cut filter. More close to 0%.

Specifically, in the light transmission characteristic L4 of the former infrared cut filter, the transmittance at a wavelength of 600 nm is about 55%, the transmittance at a wavelength of about 605 nm is 50%, and the transmittance at a wavelength of about 675 nm is 7.5% at a wavelength. The 700 nm transmittance is about 3% of light transmission.

On the other hand, with respect to the light transmission characteristic L3 (see FIG. 3) of the infrared cut filter 1 of the first embodiment, the transmittance at a wavelength of 600 nm is about 75%, the transmittance at a wavelength of about 640 nm is 50%, and the wavelength is about 675 nm. The transmittance was 20%, and the transmittance at a wavelength of 700 nm was about 0%. Further, with respect to the light transmission characteristic L7 (see FIG. 4) of the infrared cut filter 1 of the second embodiment, the transmittance at a wavelength of 600 nm is about 80%, the transmittance at a wavelength of about 650 nm is 50%, and the transmittance at a wavelength of about 675 nm. The rate was 30%, and the transmittance at a wavelength of 700 nm was about 0%. Further, with respect to the light transmission characteristic L10 (see FIG. 5) of the infrared cut filter 1 of the third embodiment, the transmittance at a wavelength of 600 nm is about 85%, the transmittance at a wavelength of about 670 nm is 50%, and the transmittance at a wavelength of about 675 nm. The rate was 40%, and the transmittance at a wavelength of 700 nm was about 0%.

As described above, the light-transmitting characteristics L3, L7, and L10 of the infrared cut filter 1 according to the first to third embodiments are different from the light-transmitting characteristic L4 of the prior infrared cut filter for the wavelength band of 600 nm to 700 nm. The transmittance in the wavelength band of 600 nm to 675 nm is very high, and the transmittance is close to 0% at a wavelength of 700 nm. In short, the infrared cut filter 1 according to the first to third embodiments is recognized as being capable of sufficiently blocking infrared rays exceeding 700 nm and sufficiently transmitting red visible light having a wavelength of 600 nm to 700 nm as compared with the conventional infrared cut filter. By. Therefore, when the infrared cut filter 1 according to the first to third embodiments is mounted on the photographing device, the photographing device 5 can capture an image having a stronger red component than before, and can image the dark portion brightly.

Further, in the infrared cut filter 1 according to the first embodiment, the infrared reflector 3 is combined with the infrared absorber 2, and the amount of light reflected by the infrared reflector 2 is suppressed. Specifically, in the infrared cut filter 1 of the first embodiment, the half value wavelength of the infrared reflector 3 is about 680 nm as shown in FIG. 3 and longer than the half value wavelength (about 640 nm) of the infrared absorber 2. Further, in the infrared cut filter 1 of the second embodiment, the half value wavelength of the infrared reflector 3 is about 680 nm as shown in FIG. 4 and longer than the half value wavelength (about 650 nm) of the infrared absorber 2. Further, in the infrared cut filter 1 of the third embodiment, the half value wavelength of the infrared reflector 3 is about 680 nm as shown in FIG. 5 and longer than the half value wavelength (about 670 nm) of the infrared absorber 2. Thus, in the infrared cut filter 1 according to the first to third embodiments, the half-value wavelength of the infrared reflector 3 (the wavelength at which the transmittance is 50%) is longer than the half-value wavelength of the infrared absorber 2, and the infrared absorber The transmittance curve of the light-transmitting characteristics L1, L5, and L8 of 2, and the wavelength of the intersection P of the infrared light-reflecting body 3 which exhibits the transmission curves of the light-transmitting characteristics L2, L6, and L9 (the transmittance of the infrared absorber 2 and The transmittance of the infrared reflector 3 is the same wavelength), and is longer than the half-value wavelength of the infrared absorber 2. Further, the transmittance of the infrared absorber 2 and the infrared reflector 3 at the wavelength of the intersection P is 50% or less. Therefore, in the infrared cut filter 1 according to the first to third embodiments, the amount of light reflected by the infrared ray reflector 3 is suppressed by the absorption of the infrared ray in the infrared ray absorbing body 2, and the light reflection of the infrared ray reflector 2 is suppressed. The occurrence of glare and ghosting.

Further, in the infrared cut filter 1 according to the first to third embodiments of the first embodiment, the half value wavelength of the infrared reflector 3 is longer than the half value wavelength of the infrared absorber 2, and the infrared absorber 2 and the infrared rays are combined. The half-value wavelength of the infrared cut filter 1 of the reflector 3 is configured to be almost uniform to the half-value wavelength of the infrared absorber 2. In short, the infrared absorber 2 having a small difference in transmittance due to a design error compared with the infrared reflector 3 has a half-value wavelength of the infrared cut filter 1 set. Therefore, the infrared cut filter 1 is used. The manufacturing can reduce the difference in light transmission characteristics of the infrared cut filter caused by design errors during manufacturing.

Further, in the infrared cut filter 1 according to the first to third embodiments of the first embodiment, the infrared reflector 3 has a transmittance of 80% or more at each wavelength in the wavelength range of 450 nm to 650 nm, at 450 nm. The transmittance of the wavelength band of -650 nm is an average of 90% or more of light transmission characteristics. Therefore, the infrared cut filter 1 can obtain a light transmitting property depending on the light transmitting property of the infrared absorbing body 2 in a wavelength band of 450 nm to 650 nm, so that the transmittance is gradually reduced across the visible light region to the infrared ray region at 700 nm. The wavelength can obtain a light transmission characteristic having a transmittance of about 0% which is close to the sensitivity characteristic of the human eye, and a high transmittance can be obtained in the visible light region, particularly in the wavelength band of the red visible light (600 nm to 700 nm).

Further, the infrared reflector 3 exhibits a transmittance of 90% or more for the half-value wavelength of the infrared absorber 2 such that the half-value wavelength of the infrared cut filter 1 almost coincides with the half-value wavelength of the infrared absorber 2. According to the configuration of the infrared absorber, the light-transmitting property of the infrared absorbing material which is close to the sensitivity characteristic of the human eye is gradually reduced at a wavelength of 550 nm to 700 nm, and is provided in the infrared cut filter 1 to obtain a light transmitting property close to the sensitivity characteristic of the human eye. .

Further, in the infrared cut filter 1 according to the first to third embodiments of the first embodiment, the infrared absorber 2 can be made thinner than the former infrared cut filter having the light transmission characteristics indicated by L4. Composition. Therefore, the thickness of the infrared cut filter 1 can be made the same thickness as the former infrared cut filter or thinner than the former infrared cut filter.

<implementation type 2>

In the infrared cut filter 1A according to the second embodiment, as shown in FIG. 6, the photographing device is disposed between the imaging optical system 4 disposed along the optical axis of the photographing optical path and the photographing device 5.

The infrared cut filter 1A according to the second embodiment of the present invention is composed of an infrared absorber 2A that absorbs infrared rays and an infrared reflector 3A that reflects infrared rays, as shown in Fig. 6 .

In the imaging device, the infrared ray absorbing body 2A and the infrared ray reflector 3A are disposed apart from each other between the imaging optical system 4 and the imaging device 5 which are arranged along the optical axis of the imaging optical path. Moreover, the infrared absorber 2A is disposed on the side close to the imaging optical system 4.

The infrared absorber 2A forms an anti-reflection film 22 on the two main faces 211 and 212 of the infrared absorbing glass 21.

As the infrared absorbing glass 21, similar to the infrared absorbing glass 21 of the infrared absorbing body 2 shown in the first embodiment, a blue glass in which a dye such as copper ions is dispersed is used, for example, a square thin plate having a thickness of 0.2 mm to 1.2 mm. Glass.

Further, the anti-reflection film 22 is a single layer or Al ₂ O formed by vacuum-depositing MgF ₂ by a conventional vacuum vapor deposition apparatus (not shown) on the two main surfaces 211 and 212 of the infrared absorbing glass 21. ₂ is formed by any one of a multilayer film composed of ZrO ₂ and MgF ₂ and a multilayer film composed of TiO ₂ and SiO ₂ . In addition, the anti-reflection film 22 performs a vapor deposition operation while monitoring the film thickness, and when a specific film thickness is reached, the shutter (not shown) provided in the vicinity of the vapor deposition source (not shown) is closed to stop the vapor deposition material. The evaporation is carried out. Such an anti-reflection film 22 is formed such that the refractive index N in the atmosphere is larger than the refractive index of the atmosphere (about 1.0) and smaller than the refractive index of the infrared absorbing glass 21.

Since the infrared absorber 2A is configured using the infrared absorbing glass 21 similar to that of the first embodiment, it has the same light transmission characteristics as the infrared absorbing body 2 of the first embodiment. In short, the transmittance at a wavelength in the wavelength band of 620 nm to 670 nm is 50%, and the transmittance at a wavelength of 700 nm is 10% to 40%. Moreover, in the light transmission characteristics of the infrared absorber 2, the wavelength in the wavelength range of 400 nm to 550 nm is 90% or more.

Further, the infrared reflector 3A is formed with an infrared reflection film 32 on one main surface 311 of the transparent substrate 31, and an anti-reflection film 33 is formed on the other main surface 312. The infrared ray reflector 3A is disposed on the imaging device as shown in FIG. 6 so that the surface on the side of the infrared ray reflection film 32 faces the imaging device 5.

As the transparent substrate 31, a colorless transparent glass that transmits visible light and infrared light similarly to the transparent substrate 31 shown in Embodiment 1 is used, and for example, a square thin plate glass having a thickness of 0.2 mm to 1.0 mm is used.

The infrared ray reflection film 32 is formed by laminating a plurality of first films 321 made of a high refractive index material similar to the infrared ray reflection film 32 shown in Embodiment 1 and a second film 322 made of a low refractive index material. Multilayer film.

Since the infrared reflecting body 3A of the above-described embodiment 1 is formed on the transparent substrate 31, the infrared reflecting film 32 similar to that of the first embodiment has the same light transmitting characteristics as the infrared reflecting body 3 of the first embodiment. In short, the infrared reflector 3A has a transmittance of 80% or more at each wavelength in the wavelength range of 450 nm to 650 nm, and an average transmittance of 90% or more in the wavelength range of 450 nm to 650 nm, and is in the range of 670 nm to 690 nm. Wavelength in the wavelength band The transmittance was 50%, and the transmittance at a wavelength of 700 nm became a light transmission characteristic of less than 15%. Further, the infrared ray reflector 3A exhibits a wavelength of 50% transmittance, which is longer than a wavelength at which the infrared absorbing body 2 exhibits a transmittance of 50%.

The anti-reflection film 33 is a single layer, Al ₂ O ₂ and ZrO _{2 which} are vacuum-deposited with MgF ₂ by a conventional vacuum vapor deposition apparatus (not shown) on the other main surface 312 of the transparent substrate 31. It is formed by any one of a multilayer film composed of MgF ₂ and a multilayer film composed of TiO ₂ and SiO ₂ . In addition, the anti-reflection film 22 performs a vapor deposition operation while monitoring the film thickness, and when a specific film thickness is reached, the shutter (not shown) provided in the vicinity of the vapor deposition source (not shown) is closed to stop the vapor deposition material. The evaporation is carried out. Such an anti-reflection film 33 is formed such that the refractive index N in the atmosphere is larger than the refractive index of the atmosphere (about 1.0) and is smaller than the refractive index of the transparent substrate 31.

Further, the total thickness of the infrared absorber 2A and the thickness of the infrared reflector 3A is, for example, 0.4 to 1.6 mm. In short, the thickness of the infrared absorber glass 21 constituting the infrared absorber 2 and the thickness of the transparent substrate 31 constituting the infrared reflector 3 are the total thickness of the infrared absorber 2 and the infrared reflector 3, and are, for example, 0.4 mm to 1.6. The mode of mm is adjusted as appropriate.

Next, in the infrared cut filter 1A, by the combination of the light transmitting characteristics of the infrared absorber 2A and the infrared reflector 3A described above, the light transmission characteristics similar to those of the infrared cut filter 1 of the first embodiment can be obtained. That is, the transmittance in the wavelength range of 450 nm to 550 nm is 90% or more, the transmittance in the wavelength range of 620 nm to 670 nm is 50%, and the transmittance at the wavelength of 700 nm becomes less than 5%. Light transmission characteristics.

As described above, in the infrared cut filter 1A according to the embodiment 2, the same light transmission characteristics as those of the infrared cut filter 1 according to the first embodiment can be obtained, so that the infrared cutoff associated with the embodiment 1 can be exhibited. Filter 1 has the same effect.

Further, in the above-described embodiments 1 and 2, a glass plate is used as the transparent substrate 31. However, it is not limited thereto, and may be a substrate that can transmit light, and may be, for example, a crystal plate. Further, the transparent substrate 31 may be a birefringent plate or a multi-refractive plate formed of a plurality of sheets. Further, the crystal plate and the glass plate may be combined to form the transparent substrate 31.

Further, in Embodiments 1 and 2, TiO ₂ is used for the first film 321, but the first film 321 is not limited thereto, and may be composed of a high refractive index material, for example, ZrO ₂ , TaO ₂ , and Nb _{2 .} O ₂ and so on. In addition, SiO ₂ is used for the second film 322. However, the second film 322 may be formed of a low refractive index material, for example, MgF ₂ or the like may be used.

Further, the infrared cut filters 1 and 1A of the first and second embodiments are disposed in the imaging device, and the infrared absorbers 2 and 2A are disposed on the side of the imaging optical system 4, but are not limited thereto. In other words, the infrared cut filters 1 and 1A may be disposed such that the infrared reflectors 3 and 3A are located closer to the side of the imaging optical system 4.

For example, in the imaging device, when the infrared ray blocking filters 1 and 2A are disposed such that the infrared absorbing bodies 2 and 2A are located on the side of the imaging optical system 4, the light reflected by the infrared ray reflectors 3 and 3A can be absorbed by infrared rays. Since the bodies 2 and 2A are absorbed, the light scattered by the infrared reflectors 3 and 3A and scattered by the imaging optical system 4 can be reduced as compared with the case where the infrared reflectors 3 and 3A are disposed on the side of the imaging optical system 4. The amount can suppress the occurrence of ghosts. On the other hand, when the infrared ray cut filters 1 and 3A are disposed such that the infrared ray reflectors 3 and 3A are located on the side of the imaging optical system 4, the infrared ray absorbing bodies 2 and 2A are disposed on the side of the imaging optical system 4. In contrast, the distance between the infrared reflectors 3 and 3A and the imaging device 5 is, in particular, the distance between the foreign matter generated in the infrared reflectors 3 and 3A during the manufacturing process and the imaging device 5 is distant, so that foreign matter can be suppressed. Degradation of the image.

Further, in the first and second embodiments, the infrared absorbing members 2 and 2A are used as the main surface 211 of the infrared absorbing glass 21 or the two main surfaces 211 and 212 to form the antireflection film 22, but the infrared absorbing body of the present invention is used. 2, 2A is not limited to this. For example, when the refractive index in the atmosphere of the infrared absorbing glass 21 is almost the same as the refractive index of the atmosphere, the antireflection film 22 may not be formed. In short, the infrared absorbing glass which is not formed with the antireflection film may be used as an infrared absorbing body.

Further, in the first embodiment, the infrared reflecting body 3 is used as the infrared reflecting body 3, and the infrared reflecting film 32 is formed on one main surface 311 of the transparent substrate 31 bonded to the other main surface 212 of the infrared absorbing glass 21. In the second embodiment, as the infrared reflector 3A, the infrared reflecting film 32 is formed on one main surface 311 of the transparent substrate 31, and the antireflection film 33 is formed on the other main surface 312. However, the infrared reflecting body 3, 3A of the present invention does not This is limited. For example, an infrared reflecting film formed on the surface of the infrared absorbing glass may be used as an infrared reflecting body.

In short, in the first embodiment, the infrared reflecting film 32 is formed on one main surface 311 of the transparent substrate 31 adhered to the other main surface 212 of the infrared absorbing glass 21, but the other main surface 212 of the infrared absorbing glass 21 is provided. The infrared reflection film 32 which is an infrared absorber can also be formed directly. As a specific example, the other main surface 212 of the infrared absorbing glass 21 may be formed by alternately vacuum-depositing TiO ₂ and SiO ₂ to form an infrared ray reflecting film 32 as an infrared absorbing body in the infrared absorbing glass 21. Main face 212. When the infrared reflecting film 32 is directly formed on the other main surface 212 of the infrared absorbing glass 21, the infrared cut filter 1 can be made thinner.

Further, in the second embodiment, the anti-reflection film 33 is formed on the other main surface 312 of the transparent substrate 31. However, when the refractive index of the transparent substrate 31 in the atmosphere is almost the same as the refractive index of the atmosphere, the anti-reflection film may not be formed. Reflective film 33.

Further, the present invention can be implemented in various other modified forms without departing from the spirit or main features. The foregoing embodiments are, therefore, to be considered in a The scope of the present invention is shown by the scope of the claims, and is not limited by the text of the specification. Further, variations or modifications of the equivalent scope of the claims are intended to be within the scope of the invention.

In addition, the present application claims priority from Japanese Patent Application No. 2010-139686, filed on Jan. As a result of this reference, all of its contents are included in this application.

[Industry use possibility]

The present invention can be applied to an infrared cut-off (IR-cut) filter that transmits light in a visible range and filters out infrared rays.

1,1A. . . Infrared cut filter

2,2A. . . Infrared absorber

twenty one. . . Infrared absorption glass

211,212. . . Main face

twenty two. . . Anti-reflection film

3,3A. . . Infrared reflector

31. . . Transparent substrate

311,312. . . Main face

32. . . Infrared reflective film

321. . . First film

322. . . Second film

33. . . Anti-reflection film

4. . . Imaging optical system

5. . . Photography device

Fig. 1 is a schematic view showing a schematic configuration of an image pickup apparatus using an infrared cut filter according to an embodiment 1.

Fig. 2 is a partially enlarged view showing a schematic configuration of an infrared reflector relating to the infrared cut filter of the first embodiment.

Fig. 3 is a view showing the light transmission characteristics of the infrared cut filter of Example 1 relating to Embodiment 1.

Fig. 4 is a view showing the light transmission characteristics of the infrared cut filter of Example 2 relating to Embodiment 1.

Fig. 5 is a view showing the light transmission characteristics of the infrared cut filter of Example 3 relating to Embodiment 1.

Fig. 6 is a schematic view showing a schematic configuration of an image pickup apparatus using an infrared cut filter according to the embodiment 2.

Fig. 7 is a view showing the light transmission characteristics of the infrared absorbing glass.

Fig. 8 is a view showing the light transmission characteristics of the infrared cut coating.

1. . . Infrared cut filter

2. . . Infrared absorber

twenty one. . . Infrared absorption glass

211,212. . . Main face

twenty two. . . Anti-reflection film

3. . . Infrared reflector

31. . . Transparent substrate

311,312. . . Main face

32. . . Infrared reflective film

4. . . Imaging optical system

5. . . Photography device

Claims (5)

An infrared cut-off filter is an infrared cut-off filter that cuts off infrared rays, and is characterized in that: an infrared absorber that absorbs infrared rays and an infrared reflector that reflects infrared rays; and the infrared absorber has a wavelength band of 620 nm to 670 nm. The transmittance of the wavelength is 50% of the light transmission property; the infrared reflector has a light transmittance of 50% in a wavelength band of 670 nm to 690 nm; and the infrared reflector exhibits a transmittance of 50%. The wavelength is longer than a wavelength at which the infrared ray absorbing body exhibits a transmittance of 50%; and the combination of the infrared ray absorbing body and the infrared ray reflector has a transmittance of 50% in a wavelength band of 620 nm to 670 nm, The transmittance at a wavelength of 675 nm is 20 to 40%, and the transmittance at a wavelength of 700 nm is less than 5%. The infrared cut filter according to claim 1, wherein the infrared absorber has a light transmittance of 10% to 40% at a wavelength of 700 nm, and the infrared reflector has a transmittance of 700 nm. Less than 15% light transmission characteristics. The infrared cut filter according to claim 1 or 2, wherein the infrared reflector has a transmittance of 80% or more at each wavelength in a wavelength range of 450 nm to 650 nm, and is in a range of 450 nm to 650 nm. The transmittance of the wavelength band averages over 90% of the light transmission characteristics. An infrared cut filter according to claim 1 or 2, wherein one of the infrared radiation absorbers is provided on one main surface of the infrared absorber. A photographic apparatus characterized by comprising an infrared cut filter of claim 1 or 2.